Search

Mesoporous particles have attracted considerable attention in drug delivery system, because they can offer fast mass transport and overcome the diffusion restriction as occurred in micro/nano- porous particles. Conventional mesoporous particles are generally dominated by inorganic compounds, little concern has been raised over biodegradable organic polymers, especially silk fibroin. Here, we show that Antheraea pernyi (A. pernyi) silk fibroin, rich in Arg-Gly-Asp (RGD) moiety, can be developed into mesoporous particles via self-assembly in a direct and eco-friendly (without any organic solvents) manner for sustained release of 5-fluorouracil (5-FU). By cultivating a mild condition at 40 ℃, a mesoporous structure was successfully achieved without any foreign organic solvents. The self-assembled mesoporous particles were quasi-spherical in shape with an average diameter of 1.58 µm. Mesopores ran through the entire particles to construct a divergent structure with external pore diameters ranging from 30 to 60 nm and internal pore width of 6.225 nm. The mesoporous particles were predominated by β -sheet conformation (∼45%), which effectively reduced the weight-loss ratio to 2.6%. 5-FU was encapsulated into the mesoporous particles by hydrogen bonding and van der Waals force as well as ionic interactions. Drug loading efficiency and encapsulation efficiency were found to be 26.24% and 50.36%, respectively. The mesoporous particles enabled sustained drug release, with approximately 90% release after 110 h. After a small burst release (20%) of the surface-bound 5-FU, a slower linear release dominated by Fickian-diffusion occurred. These features together with the excellent biocompatibility of A. pernyi silk indicated that the self-assembled mesoporous particles would be an ideal carrier for sustained drug release to meet critical requirements of biomaterials. Furthermore, without any foreign materials, this one-step strategy may offer new green chemistry approaches as well as options to load bioactive drugs. [Display omitted] • Mesoporous Antheraea pernyi particle was fabricated in a direct and eco-friendly way. • Mesopores ran through the entire particles to construct a divergent structure. • The mesoporous particles were predominated by β -sheet conformation. • The mesoporous particles enabled sustained release of 5-FU. [ABSTRACT FROM AUTHOR]

Functionalized polyamide 6 (PA 6) filament fabric with excellent thermal stability and UV resistance was copolymerized with methyl methacrylate (MMA) via in-situ grafting initiated by immobilized ascorbic acid and hydrogen peroxide. Grafting modification process was determined at 30 % of H 2 O 2 , at 70 °C for 60 min of duration, and the grafting degree could be tuned by adjusting the amount of MMA. Microscopic investigations confirmed the granular MMA was immobilized on the surface of PA 6 fibers. A strong peak at 1729 cm−1, assigning to C O stretching of ester bond of MMA, demonstrated MMA was successful grafted. The decomposition temperature of grafted PA 6 occurring at 444.6 °C, was 40 °C higher than that of pristine PA 6 (403.4 °C). Additionally, the introduction of MMA also improved the UV resistance of PA, more than 80 % decrease in transmittance of UVA band and UVB band with only 0.34 % grafting degree. Therefore, it can be concluded that in-situ grafting of MMA can endow PA 6 with excellent thermal stability and UV resistance. We believe that in-situ grafting of MMA would have important guiding significance for the fabrication of PA 6 based textiles with excellent thermal stability and UV resistance. [Display omitted] • Functionalized PA6 was copolymerized with MMA via in-situ grafting initiated by immobilized H 2 A and H 2 O 2 in aqueous solution. • The grafting degree can be tuned by the amount of MMA and the process parameters of in-situ grafting. • Thermal stability of grafted PA6 was promoted greatly with the T d 40 °C higher than that of pristine PA 6. • UUV resistance of grafted PA 6 was enhanced dramatically. [ABSTRACT FROM AUTHOR]